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block.c
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block.c
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#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "inline.h"
#include "read.h"
#include "block.h"
static int startsWith(char* string, char* prefix) {
return string != NULL && strncmp(prefix, string, strlen(prefix)) == 0;
}
static char* skip(char* start, char* characters) {
return start == NULL ? NULL : start + strspn(start, characters);
}
static char* rskip(char* end, char* characters) {
for (; strchr(characters, end[-1]); end--);
return end;
}
static char* rtrim(char* s, char* characters) {
for (size_t i = strlen(s); i > 0 && strchr(characters, s[i - 1]); i--)
s[i - 1] = '\0';
return s;
}
static char* unindent(char* p) {
return startsWith(p, " ") ? p + 4 : (p && p[0] == '\t' ? p + 1 : NULL);
}
static int isBlankLine(char* line) {
char* end = skip(line, " \t");
return end[0] == '\n' || end[0] == '\r';
}
static void processCodeFence(char* line, FILE* output) {
size_t length = strspn(line, "`");
char* language = rtrim(skip(line + length, " \t"), " \t\r\n");
if (language[0] != '\0') {
fputs("<pre>\n<code class=\"language-", output);
fputs(language, output);
fputs("\">\n", output);
} else {
fputs("<pre>\n<code>\n", output);
}
while ((line = readLine()) && strspn(line, "`") < length)
printEscaped(line, NULL, output);
fputs("</code>\n</pre>\n", output);
}
static void processCodeBlock(char* line, FILE* output) {
fputs("<pre>\n<code>\n", output);
printEscaped(unindent(line), NULL, output);
while (unindent(peekLine()))
printEscaped(unindent(readLine()), NULL, output);
fputs("</code>\n</pre>\n", output);
}
static void processMathBlock(char* line, FILE* output) {
line += 2;
fputs("\\[", output);
do {
char* end = strstr(line, "$$");
if (end && isBlankLine(end + 2)) {
printEscaped(line, end, output);
break;
}
printEscaped(line, NULL, output);
} while ((line = readLine()));
fputs("\\]\n", output);
}
static void processTableRow(char* line, int header, FILE* output) {
char* p = line + 1;
fputs("<tr>\n", output);
for (char* end = p; (end = strchr(end + 1, '|'));) {
if (end[-1] == '\\')
continue;
fputs(header ? "<th>" : "<td>", output);
processInlines(skip(p, " \t"), rskip(end, " \t"), output);
fputs(header ? "</th>\n" : "</td>\n", output);
p = end + 1;
}
fputs("</tr>\n", output);
}
static void processTable(char* line, FILE* output) {
char* nextLine = peekLine();
int divider = startsWith(nextLine, "|") &&
isBlankLine(skip(nextLine, " |-:"));
fputs("<table>\n", output);
fputs(divider ? "<thead>\n" : "<tbody>\n", output);
processTableRow(line, divider, output);
if (divider) {
fputs("</thead>\n<tbody>\n", output);
readLine();
}
while (startsWith(peekLine(), "|"))
processTableRow(readLine(), 0, output);
fputs("</tbody>\n</table>\n", output);
}
static void processDescriptionItem(char* line, FILE* output) {
char* key = skip(line + 1, " \t");
char* separator = strchr(line, ':');
if (!separator || key[0] == '.')
return;
fputs("<dt>\n", output);
processInlines(key, rskip(separator, " \t"), output);
fputs("\n</dt>\n<dd>\n", output);
char* value = rtrim(skip(separator + 1, " \t"), " \t\r\n");
processInlines(value, NULL, output);
fputs("\n</dd>\n", output);
}
static void processDescriptionList(char* line, FILE* output) {
fputs("<dl>\n", output);
processDescriptionItem(line, output);
while (startsWith(peekLine(), "= "))
processDescriptionItem(readLine(), output);
fputs("</dl>\n", output);
}
static void printHeading(char* title, int level, FILE* output) {
char openTag[] = "<h0>";
char closeTag[] = "</h0>\n";
openTag[2] = '0' + level;
closeTag[3] = '0' + level;
fputs(openTag, output);
processInlines(rtrim(skip(title, " \t"), " \t\r\n"), NULL, output);
fputs(closeTag, output);
}
static int processHeading(char* line, FILE* output) {
size_t level = strspn(line, "#");
if (level == 0 || level > 6 || !isblank(*(line + level)))
return 0;
printHeading(rtrim(skip(line + level, " \t"), " \t#\r\n"), level, output);
return 1;
}
static int processUnderline(char* line, FILE* output) {
char* next = peekLine();
if (next && next[0] == '=' && isBlankLine(skip(next, "=")))
printHeading(line, 1, output);
else if (next && next[0] == '-' && isBlankLine(skip(next, "-")))
printHeading(line, 2, output);
else return 0;
readLine();
return 1;
}
static int processFootnote(char* line, FILE* output) {
if (!startsWith(line, "[^"))
return 0;
char* name = line + 2;
char* end = strchr(name, ']');
if (end == NULL || end == name || end[1] != ':')
return 0;
fputs("<p id=\"", output);
printRaw(name, end, output);
fputs("\">\n", output);
processInlines(skip(end + 2, " \t"), NULL, output);
while (isspace(peek())) // allows blank lines
processInlines(skip(readLine(), " \t"), NULL, output);
fputs("</p>\n", output);
return 1;
}
static int isParagraphInterrupt(char* line) {
static char* interrupts[] = {"$$", "```", "---", "* ", "- ", "+ ", "> ",
"/// ", "= ", "| ", "# ", "## ", "### ", "#### ", "##### ", "###### "};
if (!line || isBlankLine(line))
return 1;
for (size_t i = 0; i < sizeof(interrupts)/sizeof(char*); i++)
if (startsWith(line, interrupts[i]))
return 1;
if (isdigit(line[0]) && line[1] == '.' && line[2] == ' ')
return 1;
return 0;
}
static void processParagraph(char* line, FILE* output) {
fputs("<p>\n", output);
processInlines(line, NULL, output);
while (!isParagraphInterrupt(peekLine()))
processInlines(readLine(), NULL, output);
fputs("</p>\n", output);
}
void processBlock(char* line, FILE* output) {
if (isBlankLine(line))
return;
if (startsWith(line, "---"))
fputs("<hr>\n", output);
else if (unindent(line))
processCodeBlock(line, output);
else if (startsWith(line, "```"))
processCodeFence(line, output);
else if (startsWith(line, "$$"))
processMathBlock(line, output);
else if (startsWith(line, "| "))
processTable(line, output);
else if (startsWith(line, "= "))
processDescriptionList(line, output);
else {
if (processHeading(line, output))
return;
if (processUnderline(line, output))
return;
if (processFootnote(line, output))
return;
processParagraph(line, output);
}
}